Method and structure for reworking antireflective coating over semiconductor substrate

ABSTRACT

A method and a structure for reworking an antireflective coating (ARC) layer over a semiconductor substrate. The method includes providing a substrate having a material layer, forming a planarization layer on the material layer, forming an organic solvent soluble layer on the planarization layer, forming an ARC layer on the organic solvent soluble layer, forming a pattern in the ARC layer, and removing the organic solvent soluble layer and the ARC layer with an organic solvent while leaving the planarization layer unremoved. The structure includes a substrate having a material layer, a planarization layer on the material layer, an organic solvent soluble layer on the planarization layer, and an ARC layer on the organic solvent soluble layer.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of co-pending U.S.application Ser. No. 12/610,679, filed on Nov. 2, 2009, the contents ofwhich are incorporated by reference in its entirety herein.

FIELD OF THE INVENTION

The present invention relates generally to semiconductor deviceprocessing and, more particularly, to reworking antireflective coatinglayers over a semiconductor substrate.

BACKGROUND OF THE INVENTION

As feature sizes continue to scale down in semiconductor industry, thefabrication process of integrated circuit devices becomes more and morecomplex. Advanced semiconductor designs typically incorporate multilayerstructures. For example, during the process of formation of a metalinterconnect, usually a hardmask layer, a planarization layer and anantireflective coating (ARC) layer are sequentially formed on asubstrate with a dielectric layer thereon. A photoresist layer is thenformed on top of the ARC layer. The definition of the pattern is formedby photolithography on the photoresist layer. The resist pattern istransferred to the ARC layer via an etch process using the photoresistfilm as a mask. Similarly, the ARC pattern is transferred sequentiallythrough all other underlying layers, and finally, a pattern is formed onthe substrate.

During the deposition or the processing of the multilayer structures, ifdefects or other types of errors are found in any layer of thestructures, the substrate must be reworked to prevent permanent damageto the entire batch of chips in subsequent processing. In addition,selective removing the multilayer structures is often necessary forpurposes of performing defect yield analysis, and/or for electricalcharacterization or physical failure analysis of wafers, waferfragments, individual dies, or packaged dies to perform reliabilitydefect root cause analysis.

Reworking multilayer structures including low-k dielectric materials isproblematic using known layer removal techniques such as conventionalchemical-mechanical polish (CMP), or plasma or reactive ion etchprocesses. The fragile nature of the low-k dielectric materials causesthem to react poorly to processes effective for oxide dielectrics. Inaddition, conventional layer removal processes used to remove overlyinglayers can result in damages to the underlying low-k dielectric layers.

New and improved processes are thus desirable which can selectivelyrework overlying layers without damaging the underlying low-k dielectriclayers on a multilayer semiconductor substrate.

SUMMARY OF THE INVENTION

The present invention provides a method and a structure for reworking anantireflective coating (ARC) layer over a semiconductor substratewithout causing damage to an underlying dielectric layer.

A first embodiment introduces a method of reworking an antireflectivecoating (ARC) layer over a substrate. The method includes the steps ofproviding a substrate having a material layer; forming a planarizationlayer on the material layer; forming an organic solvent soluble layer onthe planarization layer; forming an ARC layer on the organic solventsoluble layer; forming a pattern in the ARC layer; and removing theorganic solvent soluble layer and the ARC layer with an organic solventwhile leaving the planarization layer unremoved.

A second embodiment introduces a method of reworking an ARC layer over asubstrate. The method includes the steps of providing a semiconductorsubstrate having a material layer and a hardmask layer on the materiallayer; forming an organic solvent soluble layer on the hardmask layer;forming a planarization layer on the organic solvent soluble layer;forming an ARC layer on the planarization layer; forming a pattern inthe ARC layer; and removing the organic solvent soluble layer, the ARClayer and the planarization layer with an organic solvent.

A third embodiment introduces a method of forming a patterned materialstructure on a substrate. The method includes the steps of providing asubstrate having a material layer; forming a planarization layer on thematerial layer; forming a first organic solvent soluble layer on theplanarization layer; forming a first ARC layer on the first organicsolvent soluble layer; forming a first pattern in the first ARC layer;removing the first organic solvent soluble layer and the first ARC layerwith an organic solvent while leaving the planarization layer unremoved;forming a second organic solvent soluble layer on the planarizationlayer; forming a second ARC layer on the second organic solvent solublelayer; forming a second pattern in the second ARC layer; andtransferring the second pattern to the material layer.

A fourth embodiment introduces a method of forming a patterned materialstructure on a substrate. The method includes the steps of providing asubstrate having a material layer and a hardmask layer on the materiallayer; forming a first organic solvent soluble layer on the hardmasklayer; forming a first planarization layer on the first organic solventsoluble layer; forming a first ARC layer on the first planarizationlayer; forming a first pattern in the first ARC layer; removing thefirst organic solvent soluble layer, the first ARC layer and the firstplanarization layer with an organic solvent leaving the hardmask layerunremoved; forming a second organic solvent soluble layer on thehardmask layer; forming a second planarization layer on the secondorganic solvent soluble layer; forming a second ARC layer on the secondplanarization layer; forming a second pattern in the second ARC layer;and transferring the second pattern to the material layer.

A fifth embodiment introduces a multilayer structure including asubstrate having a material layer; a planarization layer on the materiallayer; an organic solvent soluble layer on the planarization layer; andan ARC layer on the organic solvent soluble layer.

A sixth embodiment introduces a multilayer structure including asemiconductor substrate having a material layer and a hardmask layer onthe material layer; an organic solvent soluble layer on the hardmasklayer; a planarization layer on the organic solvent soluble layer; andan ARC layer on the planarization layer.

The above described and other features are exemplified by the followingfigures and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a flow chart illustrating a method of reworking an ARC layeron a substrate, in accordance with the present invention.

FIGS. 2-28 are cross-sectional views that illustrate exemplaryprocessing steps of a method of reworking an ARC layer on a substrate,in accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which preferred embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theillustrated embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.Like numerals refer to like features throughout. Features of theinvention are not necessarily shown to scale in the drawings.

It will be understood that when an element, such as a layer, is referredto as being “on” or “over” another element, it can be directly on theother element or intervening elements may also be present. In contrast,when an element is referred to as being “directly on” or “directly over”another element, there are no intervening elements present.

The present invention provides a method and a structure for removing anARC layer over a semiconductor substrate without causing damage to anunderlying dielectric layer. In this method, the substrate has amaterial layer and a hardmask layer on the material layer. An organicsolvent soluble layer is first formed on the hardmask layer. An ARClayer is then formed on the organic solvent soluble layer. Thereafter, aresist pattern is formed on the ARC layer. The resist pattern istransferred to the ARC layer through an etch transfer process. Ifdefects or other types of errors are found on the ARC pattern, theorganic solvent soluble layer can be removed by using an organic solventthereby releasing the ARC layer on top of the organic solvent solublelayer while leaving the layers underneath the organic solvent solublelayer unremoved.

FIG. 1 is a flow chart illustrating a method of reworking an ARC layeron a substrate according to one embodiment of the present invention.

In Step 100, a substrate having a material layer is provided. Thesubstrate in the present invention is suitably any substrateconventionally used in processes involving photoresists. For example,the substrate can be silicon, silicon oxide, aluminum-aluminum oxide,gallium arsenide, ceramic, quartz, copper or any combination thereof,including multilayers. The substrate can include one or moresemiconductor layers or structures and can include active or operableportions of semiconductor devices.

The material layer may be an organic dielectric, a metal, a ceramic, ora semiconductor. Preferably, the material layer is an organic dielectriclayer (ODL).

In Step 110, a planarization layer is formed on the material layer.Preferably, the planarization layer is an organic planarization layer(OPL). Examples of OPL suitable for the present invention include, butare not limited to, CHM701B, commercially available from Cheil ChemicalCo., Ltd., HM8006 and HM8014, commercially available from JSRCorporation, and ODL-102, commercially available from ShinEtsu Chemical,Co., Ltd.

In Step 120, an organic solvent soluble layer is formed on theplanarization layer. The organic soluble layer is a polymer or a mixtureof polymers soluble in organic solvents. Examples of polymers suitablefor the present invention include, but are not limited to, polysulfone,polyarylsulfone, polyethersulfone, polyimide, and polyarylether.Preferably, the organic solvent soluble layer is polyarylsulfone. Oneexample of polyarylsulfone that may be used within the context of thepresent invention is UDEL™, commercially available from AmocoCorporation.

The organic soluble layer may also comprise a dye which provides theorganic soluble layer with desired optical properties for improvedanti-reflective effects. Preferably, the organic soluble layer has arefractive index (n) in the range from about 1.4 to about 2.0 and anabsorption parameter (k) in the range from about 0.1 to about 0.6 at theimaging wavelength used to create the resist pattern. More preferably,the organic soluble layer has a refractive index (n) in the range fromabout 1.6 to about 1.8 and an absorption parameter (k) in the range fromabout 0.2 to about 0.5 at the imaging wavelength used to create theresist pattern.

In Step 130, an ARC layer is formed on the organic solvent solublelayer. The ARC layer may suitably be any ARC conventionally used inprocesses involving photoresists. Preferably, the ARC layer is a siliconARC (SiARC) layer.

In Step 140, a pattern is formed in the ARC layer. The ARC pattern maybe formed by using a photoresist layer with a resist pattern as a mask.The resist pattern may be transferred to the ARC layer by an etchtransfer process.

If a substrate has a failed ARC pattern, then the ARC layer is removedin Step 150. A failed ARC pattern means, for example, an ARC patternwhose size is out of spec, or an ARC pattern in which a patterndeviation is generated.

In Step 150, an organic solvent is used to remove the organic solventsoluble layer and the overlying ARC layer from the substrate. Theorganic solvent dissolves the organic solvent soluble layer and releasesthe ARC layer on top of the organic solvent soluble layer. Examples oforganic solvents suitable for the present invention may include, but arenot limited to, cyclopentanone, cyclohexanone, γ-butyrolactone,N-methyl-2-pyrrolidone (NMP), and a mixture of γ-butyrolactone (GBL) andN-butyl acetate (NBA) such as VT7000 (70% of GBL and 30% of NBA),commercially available from General Chemical West, or QZ 3501 (70% ofGBL and 30% of NBA), commercially available from Fujifilm ElectronicMaterials. Above solvents may be used alone or in admixture. The organicsolvent does not dissolve the planarization layer. Therefore, theplanarization layer and the layers below the planarization layer remainunremoved.

FIGS. 2-11 are cross-sectional views illustrating exemplary processingsteps in accordance with embodiments of the present invention. In FIG.2, a substrate 200 with a material layer 202 on top of the substrate isprovided, such as described in Step 100 above. The material layer 202 ispreferably an ODL. The ODL preferably has a thickness in the range fromabout 50 nm to about 500 nm, more preferably, from about 100 nm to about250 nm.

In FIG. 3, a planarization layer 206 is formed on the material layer202, such as described in Step 110 above. The planarization layer 206preferably has a thickness in the range from about 20 nm to about 500nm, more preferably, from about 100 nm to about 300 nm.

The present invention may also include forming a hardmask layer 204either before or after the planarization layer 206 is formed. If thehardmask layer 204 is formed before the formation of the planarizationlayer 206, then the hardmask layer 204 is between the material layer 202and the planarization layer 206 (FIG. 4A). If the hardmask layer 204 isformed after the formation of the planarization layer 206, then thehardmask layer 204 is above the planarization layer 206 (FIG. 4B).

The hardmask layer 204 may be any material that generally serves thefunction of a hardmask layer, i.e., provides a differential etch barrierto maintain an image defined during the initial processing until thefinial processing is complete. Examples of materials suitable for thehardmask layer 204 include, but are not limited to, silicon dioxide,spin-on glass, tetraethyl orthosilicate (TEOS), silicon nitride, andmetal nitrides such as titanium nitride and tantalum nitride. Thehardmask layer preferably has a thickness in the range from about 10 nmto about 100 nm, more preferably, from about 10 nm to about 50 nm.

In FIG. 5, an organic solvent soluble layer 208 is formed on theplanarization layer 206, such as described in Step 120 above. Theorganic soluble layer may be formed by any standard means for forming acoating including spin coating. The organic soluble layer may be bakedto remove any solvent from the organic soluble layer and improve thecoherence of the organic soluble layer. The preferred range of the baketemperature for the organic soluble layer is from about 100° C. to about250° C., more preferably from about 150° C. to about 200° C. Thepreferred range of thickness of the organic soluble layer is from about10 nm to about 200 nm, more preferably from about 20 nm to about 100 nm.

In FIG. 6, an ARC layer 210 is formed on the organic solvent solublelayer 208, such as described in Step 130 above. The ARC layer 210 ispreferably a silicon-containing ARC layer. The ARC layer 210 may beformed by any standard means for forming a coating including spincoating an ARC layer solution. It is preferred that the solvent of theARC layer solution does not dissolve the underlying organic solventsoluble layer 208. The ARC layer 210 may be baked to remove any solventfrom the ARC layer and cause the polymer in the ARC layer to crosslink.The preferred range of the bake temperature for the ARC layer is fromabout 100° C. to about 250° C., more preferably from about 150° C. toabout 200° C. The ARC layer preferably has a thickness in the range fromabout 20 nm to about 150 nm, more preferably, from about 25 nm to about80 nm.

In FIG. 7, a photoresist layer 212 is formed on the ARC layer 210. Thephotoresist may be any photoresist conventionally used in semiconductorindustry, including 193 nm and 248 nm photoresists. Both positive-toneresists and negative-tone resists are suitable to be used in the presentinvention. The photoresist layer 212 may be formed by virtually anystandard means including spin coating. The photoresist layer 212 may bebaked (post applying bake (PAB)) to remove any solvent from thephotoresist and improve the coherence of the photoresist layer. Thepreferred range of the PAB temperature for the photoresist layer 212 isfrom about 70° C. to about 150° C., more preferably from about 90° C. toabout 130° C. The preferred range of thickness of the photoresist layer212 is from about 20 nm to about 400 nm, more preferably from about 50nm to about 300 nm.

In FIG. 8, a resist pattern 212A is formed in the photoresist layer 212.The resist pattern may be formed by exposing the photoresist layer 212to a radiation having an imaging wavelength. The radiation employed inthe present invention can be visible light, ultraviolet (UV), extremeultraviolet (EUV) and electron beam (E-beam). It is preferred that theimaging wavelength of the radiation is about 365 nm, 248 nm, 193 nm or13 nm. More preferably, the imaging wavelength of the radiation is about193 nm.

After exposure, the photoresist layer 212 is developed in an aqueousbase solution to form a resist pattern 212A in the photoresist layer212. It is preferred that the aqueous base solution istetramethylammonium hydroxide (TMAH) solutions. It is further preferredthat the concentration of the TMAH solutions is about 0.263 N. Theaqueous base solution may further comprise additives, such assurfactants, polymers, isopropanol, ethanol, etc.

A post exposure bake (PEB) step may be performed after the photoresistlayer 212 is exposed with the radiation and before it is developed. Thepreferred range of the PEB temperature is from about 70° C. to about120° C., more preferably from about 90° C. to about 110° C. In someinstances, it is possible to avoid the PEB step since for certainchemistries, such as acetal and ketal chemistries, deprotection of theresist polymer proceeds at room temperature.

In FIGS. 9A and 9B, the resist pattern 212A is transferred into the ARClayer 210 by removing portions of the ARC layer 210 not covered by thepatterned photoresist layer 212. Typically, portions of the ARC layerare removed by reactive ion etching or some other technique known to oneskilled in the art.

In one embodiment of the present invention, the photoresist layer 212may be completely consumed in the etch transfer process (FIG. 9A). Inanother embodiment, there may be still remaining resist layer 212B afterthe etch transfer process (FIG. 9B). In either case, the ARC patternformed by the above-mentioned method may have defects due to conditionsof the etch transfer process and exterior variables. For example, aresidual ARC material may remain at the bottom of a trench 210B in theARC layer (FIGS. 9A and 9B). When this happens, the ARC layer 210 needsto be removed from the substrate 200.

The ARC layer 210 may be substantially removed by using an organicsolvent to dissolve the organic solvent soluble layer 208 therebyreleasing the overlying ARC layer 210 (FIG. 10). The organic solventdoes not dissolve the underlying planarization layer 206. Thus, theplanarization layer 206, the hardmask layer 204, and the material layer202 remain unremoved.

The removal of the organic solvent soluble layer 208 and the overlyingARC layer 210 may be accomplished by contacting the substrate 200 withan organic solvent for a period ranging from 30 seconds to 120 secondsor by dispensing an organic solvent on the substrate 200 and thenallowing the fluid to spread evenly by centrifugal force. Additionally,the organic solvent soluble layer 208 may be removed by a wet stripprogram recipe which provides for a solvent soak of the substratesurface followed by a rapid spin. The solvent soak may be performed bydispensing an organic solvent on the surface of the substrate 200. Inthis process, the substrate 200 may be slowly rotated to ensure theentire surface is covered by the solvent and to refresh the solventlayer on the substrate with additional fresh solvent. A typical soaktime with the dispensing process is from about 30 seconds to about 60seconds. A typical rotation rate is below 200 rpm and more preferablybelow 50 rpm. For a challenging material that resists rework, a longersoak time may be performed by immersing the substrate in an organicsolvent. In some cases when the solvent soak process is a batch processrather than a single wafer process, a soak time of about 60 minutes maybe needed to remove the organic solvent soluble layer 208.

Optionally, a dry strip process may be performed before the wet stripprocess, i.e., removing the organic solvent soluble layer 208 and theoverlying layers with an organic solvent. The dry strip process canfacilitate the wet strip process by increasing solvent penetration intothe organic solvent soluble layer 208 in the wet strip process.Preferably, the dry strip process is performed under a mild conditionsuch that no significant plasma hardening of the organic soluble layer208 occurs during the dry strip process. In one preferred embodiment,the remaining photoresist layer 212 and about 50 Å of the ARC layer 210are removed during the dry strip process. Suitable dry strip processesinclude, but are not limited to, an ashing process using a downstreamashing tool and an etch process using a regular etch chamber such as aDual Frequency Capacitive Coupled (DFC) or an Inductively Coupled (ICP)platform available from such vendors as AMAT, Lam Research, or TEL. Inboth instances, etch gases such as N₂, H₂, CF₄, CO₂, CO, and O₂ can beused in various combinations to achieve the mild strip condition goal.

The dry strip process can be performed in a wide range of pressure andpower settings depending on the dry strip tool of choice. For example,when a DFC plasma etch chamber is used, it is preferred that thepressure setting is from about 30 mTorr to about 150 mTorr, the sourcepower setting is from about 100 W to about 500 W, and the reflective(bottom) power setting is from about 0 W to about 300 W.

Still optionally, a second dry strip process may be employed after thewet strip process as a clean up to remove any remnant photoresist layer212, ARC layer 210 and organic solvent soluble layer 208 and as asurface preparation for the subsequent reapplication of differentlayers. Preferably, the second dry strip process is performed under amild condition such that no significant thickness loss of the underlyingplanarization layer 206 occurs and no significant undesirable plasmadefects is formed in the planarization layer 206 during the second drystrip process. In one preferred embodiment, any remnant resist layer212, ARC layer 210 and organic solvent soluble layer 208, as well asabout 50 Å of the planarization layer 206 are removed during the drystrip process. Suitable dry strip processes include, but are not limitedto, an ashing process using a downstream ashing tool and an etch processusing a regular etch chamber such as a Dual Frequency Capacitive Coupled(DFC) or an Inductively Coupled (ICP) platform available from suchvendors as AMAT, Lam Research, or TEL. In both instances, etch gasessuch as N₂, H₂, CF₄, CO₂, CO, and O₂ can be used in various combinationsto achieve the mild strip condition goal.

The second dry strip process can be performed in a wide range ofpressure and power settings depending on the dry strip tool of choice.For example, when a DFC plasma etch chamber is used, it is preferredthat the pressure setting is from about 30 mTorr to about 150 mTorr, thesource power setting is from about 100 W to about 500 W, and thereflective (bottom) power setting is from about 0 W to about 300 W.

After the defected ARC layer 210 is removed, a second organic solventsoluble layer 214 is formed on the planarization layer 206 followed bythe formation of a second ARC layer 216 on the second organic solventsoluble layer 214 (FIG. 11). The second organic solvent soluble layer214 may be the same material as or a different material from the firstorganic solvent soluble layer 208. Examples of polymers suitable for thesecond organic solvent soluble layer 214 include, but are not limitedto, polysulfone, polyarylsulfone, polyethersulfone, polyimide, andpolyarylether. Preferably, the second organic solvent soluble layer 214is polyarylsulfone. The second organic solvent soluble layer 214 mayalso comprise a dye which provides the second organic solvent solublelayer 214 with desired optical properties for improved anti-reflectiveeffects. The second organic solvent soluble layer 214 may be formed byany standard means for forming a coating including spin coating. Thesecond organic solvent soluble layer 214 may be baked to remove anysolvent from the second organic solvent soluble layer 214 and improvethe coherence of the second organic solvent soluble layer 214.

The second ARC layer 216 may be the same ARC material as or a differentARC material from the first ARC layer 210. The second ARC layer 216 ispreferably a SiARC layer. The second ARC layer 216 may be formed by anystandard means for forming a coating including spin coating an ARC layersolution. The ARC layer 216 may be baked to remove any solvent from thesecond ARC layer 216 and cause the polymer in the second ARC layer tocrosslink. The preferred range of the bake temperature for the secondARC layer 216 is from about 100° C. to about 250° C., more preferablyfrom about 150° C. to about 200° C. The second ARC layer 216 preferablyhas a thickness in the range from about 20 nm to about 150 nm, morepreferably, from about 25 nm to about 80 nm.

A second photoresist layer 218 is then formed on the second ARC layer216 (FIG. 12). The second photoresist layer 218 may be the samephotoresist as or a different photoresist from the first photoresistlayer 212. The photoresist may be any photoresist conventionally used insemiconductor industry, including 193 nm and 248 nm photoresists. Bothpositive-tone resists and negative-tone resists are suitable to be usedin the present invention. The second photoresist layer 218 may be formedby virtually any standard means including spin coating. The secondphotoresist layer 218 may be baked (PAB) to remove any solvent from thephotoresist and improve the coherence of the photoresist layer. Thepreferred range of the PAB temperature for the second photoresist layer218 is from about 70° C. to about 150° C., more preferably from about90° C. to about 130° C. The preferred range of thickness of the secondphotoresist layer 218 is from about 20 nm to about 400 nm, morepreferably from about 50 nm to about 300 nm.

In FIG. 13, a resist pattern 218A is formed in the second photoresistlayer 218. The resist pattern may be formed by exposing the secondphotoresist layer 218 to a radiation having an imaging wavelength. Theradiation employed in the present invention can be visible light,ultraviolet (UV), extreme ultraviolet (EUV) and electron beam (E-beam).It is preferred that the imaging wavelength of the radiation is about365 nm, 248 nm, 193 nm or 13 nm. It is more preferred that the imagingwavelength of the radiation is about 193 nm.

After exposure, the second photoresist layer 218 is developed in anaqueous base solution to form the resist pattern 218A in the secondphotoresist layer 218. It is preferred that the aqueous base solution istetramethylammonium hydroxide (TMAH) solutions. It is further preferredthat the concentration of the TMAH solutions is about 0.263 N. Theaqueous base solution may further comprise additives, such assurfactants, polymers, isopropanol, ethanol, etc.

A PEB step may be performed after the second photoresist layer 218 isexposed with the radiation and before it is developed. The preferredrange of the PEB temperature is from about 70° C. to about 120° C., morepreferably from about 90° C. to about 110° C. In some instances, it ispossible to avoid the PEB step since for certain chemistries, such asacetal and ketal chemistries, deprotection of the resist polymerproceeds at room temperature.

In FIG. 14, the resist pattern 218A is transferred into the second ARClayer 216 by removing portions of the ARC layer 216 not covered by thepatterned second photoresist layer 218. Typically, portions of thesecond ARC layer 216 are removed by reactive ion etching or some othertechnique known to one skilled in the art. In one embodiment of thepresent invention, the resist layer 218 may be completely consumed inthe etch transfer process. In another embodiment, there may be stillremaining resist layer 218B after the etch transfer process (FIG. 14).

If the ARC pattern 216A formed by the above-mentioned method containsdefects again, the steps illustrated in FIGS. 10-14 may be repeated inorder to form a defect-free ARC pattern.

The ARC pattern 216A can be further transferred sequentially to theunderlying layers and eventually to the material layer 202 by removingportions of the underlying layers not covered by the patterned secondARC layer 216 (FIG. 15). Typically, the pattern transfer is establishedby reactive ion etching or some other technique known to one skilled inthe art.

Alternatively, the organic solvent soluble layer 208 may be formed underthe planarization layer 206. In this case, both of the ARC layer 210 andthe planarization layer 206 may be removed by dissolving the underlyingorganic solvent soluble layer 208 in an organic solvent.

Referring to FIGS. 16-28, the organic solvent soluble layer 208 isformed on a substrate 200 having a material layer 202 and a hardmasklayer 204 (FIG. 16). The planarization layer 206 is then formed on theorganic solvent soluble layer 208 (FIG. 17). It is preferred that thesolvent of the planarization layer solution does not dissolve theunderlying organic solvent soluble layer 208. The organic solventsoluble layer 208 and the planarization layer 206 are formed the sameway as previously described.

The ARC layer 210 is formed on the planarization layer 206 (FIG. 18).The photoresist layer 212 is then formed on the ARC layer 210 (FIG. 19).The ARC layer 210 and the photoresist layer 212 are formed the same wayas previously described.

In FIG. 20, the photoresist layer 212 is exposed to form a resistpattern 212A, the same way as previously described. In FIG. 21, theresist pattern 212A is transferred to the ARC layer 210 to form an ARCpattern 210A preferably through an etch transfer process. In oneembodiment of the present invention, the resist layer 212 may becompletely consumed in the etch transfer process. In another embodiment,there may be still remaining resist layer 212B after the etch transferprocess (FIG. 21). As shown in FIG. 21, the ARC pattern formed maycontain defects such as a residual ARC material at the bottom of atrench 210B in the ARC layer.

The remaining resist layer 212 and ARC layer 210 as well as theplanarization layer 208 may be substantially removed by using an organicsolvent to dissolve the organic solvent soluble layer 208 therebyreleasing the overlying resist layer 212, ARC layer 210 andplanarization layer 208 (FIG. 22). The organic solvent does not dissolvethe underlying hardmask layer 204. Thus, the hardmask layer 204 and thematerial layer 202 remain unremoved.

As described above, the removal of the organic solvent soluble layer 208and the overlying resist layer 212, ARC layer 210 and planarizationlayer 208 may be accomplished by contacting the substrate 200 with anorganic solvent for a period ranging from 30 seconds to 120 seconds orby dispensing an organic solvent on the substrate 200 and then allowingthe fluid to spread evenly by centrifugal force. Additionally, theorganic solvent soluble layer 208 may be removed by a wet strip programrecipe which provides for a solvent soak of the substrate surfacefollowed by a rapid spin. The solvent soak may be performed bydispensing an organic solvent on the surface of the substrate 200. Inthis process, the substrate 200 may be slowly rotated to ensure theentire surface is covered by the solvent and to refresh the solventlayer on the substrate with additional fresh solvent. A typical soaktime with the dispensing process is from about 30 seconds to about 60seconds. A typical rotation rate is below 200 rpm and more preferablybelow 50 rpm. For a challenging material that resists rework, a longersoak time may be performed by immersing the substrate in an organicsolvent. In some cases when the solvent soak process is a batch processrather than a single wafer process, a soak time of about 60 minutes maybe needed to remove the organic solvent soluble layer 208.

Optionally, a dry strip process may be performed before the wet stripprocess, i.e., removing the organic solvent soluble layer 208 with anorganic solvent. Still optionally, a second dry strip process may beemployed after the wet strip process as a clean up to remove any remnantresist layer 212, ARC layer 210, planarization layer 206 and organicsolvent soluble layer 208 and as a surface preparation for thesubsequent reapplication of different layers.

After the defected ARC layer 210 and the planarization layer 208 areremoved, a second organic solvent soluble layer 214 is formed on thehardmask layer 204 followed by the formation of a second planarizationlayer 220 on the second organic solvent soluble layer 214 (FIG. 23). Thesecond organic solvent soluble layer 214 is formed the same way aspreviously described. The second planarization layer 220 may be the sameplanarization material as or a different planarization material from thefirst planarization layer 206.

The second ARC layer 216 is then formed on the second planarizationlayer 220, followed by the formation of the second photoresist layer 218on the second ARC layer 216 (FIGS. 24-25). The second ARC layer 216 andthe second photoresist layer 218 are formed the same way as previouslydescribed.

In FIG. 26, the second photoresist layer 218 is exposed to form a resistpattern 218A. The resist pattern 218A is then transferred to the secondARC layer 216 to form an ARC pattern 216A, preferably through an etchtransfer process (FIG. 27).

If the ARC pattern 216A formed by the above-mentioned method containsdefects again, the steps illustrated in FIGS. 22-27 may be repeated inorder to form a defect-free ARC pattern.

The ARC pattern 216A can be further transferred sequentially to theunderlying layers and eventually to the material layer 202 by removingportions of the underlying layers not covered by the patterned secondARC layer 216 (FIG. 28). Typically, the pattern transfer is establishedby reactive ion etching or some other technique known to one skilled inthe art.

While the present invention has been particularly shown and describedwith respect to preferred embodiments, it will be understood by thoseskilled in the art that the foregoing and other changes in forms anddetails may be made without departing from the spirit and scope of theinvention. It is therefore intended that the present invention not belimited to the exact forms and details described and illustrated butfall within the scope of the appended claims.

What is claimed is:
 1. A method of reworking an antireflective coating(ARC) layer, comprising the steps of: providing a substrate having amaterial layer; forming a planarization layer on the material layer;forming an organic solvent soluble layer on the planarization layer;forming an ARC layer on the organic solvent soluble layer; forming apattern in the ARC layer; and removing the organic solvent soluble layerand the patterned ARC layer together with an organic solvent whileleaving the planarization layer unremoved, wherein the organic solventsoluble layer remains fully soluble after the patterning of the ARClayer, and wherein the organic solvent completely removes the organicsolvent soluble layer and the ARC layer.
 2. The method of claim 1,further comprising: after providing the substrate and before forming theplanarization layer, forming a hardmask layer on the material layer,wherein the hardmask layer is between the material layer and theplanarization layer.
 3. The method of claim 1, further comprising: afterforming the planarization layer and before forming the organic solventsoluble layer, forming a hardmask layer on the planarization layer,wherein the hardmask layer is between the planarization layer and theorganic solvent soluble layer.
 4. The method of claim 1, wherein thematerial layer is an organic dielectric, a metal, a ceramic, or asemiconductor.
 5. The method of claim 1, wherein the ARC layer is asilicon ARC layer.
 6. The method of claim 1, wherein the organic solventsoluble layer comprises polysulfone, polyarylsulfone, polyethersulfone,polyimide, or polyarylether.
 7. The method of claim 6, wherein thethickness of the organic solvent soluble layer is in the range fromabout 20 nm to about 100 nm.
 8. The method of claim 1, wherein theorganic solvent is selected from the group consisting of cyclopentanone,cyclohexanone, γ-butyrolactone, N-methyl-2-pyrrolidone (NMP), a mixtureof γ-butyrolactone (GBL) and N-butyl acetate (NBA), and a combination oftwo or more of the foregoing solvents.
 9. The method of claim 1, whereinforming the pattern on the ARC layer comprises: forming a photoresistlayer on the ARC layer; forming a resist pattern in the photoresistlayer; and forming a pattern on the ARC layer by using the photoresistlayer on which the resist pattern is formed as a mask.
 10. The method ofclaim 9, wherein forming the resist pattern in the photoresist layercomprises exposing the photoresist layer with an imaging radiation. 11.The method of claim 10, wherein the organic solvent soluble layer has arefractive index (n) in the range from about 1.6 to about 1.8 and anabsorption parameter (k) in the range from about 0.2 to about 0.5 at thewavelength of the imaging radiation.